In the electronics industry, high integration and multiple functions with high performance become essential for new products. And meanwhile, high integration may cause higher manufacturing cost, since the manufacturing cost is in proportional to its size. Therefore, demanding on miniaturization of integrated circuit (IC) packages has become more and more critical. Package-on-package (PoP) is now the fastest growing semiconductor package technology since it is a cost-effective solution to high-density system integration in a single package. However, since the PoP structure has a thin thickness, the PoP structure is easy to crack or damage due to heating or other factors.
Therefore, it is important to solve or improve the above problem.